[BruceBanner]

I'm not really into printing properly yet. As I stumble more into this aspect I am wondering if there are general accepted recommendations for mega pixels vs print size that is unwise to surpass.

For example, could we print a K-1 shot at 36mp to A2 with acceptable results, yet the KP at 24mp to A2 will start to show its flaws?

Or... perhaps another way to put it... does the megapixels really translate to print? If the intended size is A2 or A3+ and the same scene is shot with a KP (24mp) and K-1 (36mp), are the differences easily noticed in terms of details/sharpness, or does the printing technology (in terms of sharpness/details) lag behind the digital display and such tolerances are harder to notice?


TIA

BB

[Benz3ne]

I'm not really into printing properly yet. As I stumble more into this aspect I am wondering if there are general accepted recommendations for mega pixels vs print size that is unwise to surpass.

For example, could we print a K-1 shot at 36mp to A2 with acceptable results, yet the KP at 24mp to A2 will start to show its flaws?

Or... perhaps another way to put it... does the megapixels really translate to print? If the intended size is A2 or A3+ and the same scene is shot with a KP (24mp) and K-1 (36mp), are the differences easily noticed in terms of details/sharpness, or does the printing technology (in terms of sharpness/details) lag behind the digital display and such tolerances are harder to notice?


TIA

BB

Howdy BB, I think it also dependent on how far away you are from the print in question, but I could be wrong.
How big do you want to print? That'd probably help direct you to an answer too.
P.s. Loving your photos (I see them on Facebook and Flickr )

[pschlute]

I'm not really into printing properly yet. As I stumble more into this aspect I am wondering if there are general accepted recommendations for mega pixels vs print size that is unwise to surpass.

I tend to use 300 ppi (pixels per inch). This is what the commercial printer I use specifies and seems to be a standard. So the max recommended from a K1 file is 24*16 inches.

If you want larger you can:

1 Upsample the image to a larger pixel resolution. or

2. Print at a lower ppi.

[house]

There are rules of thumb but the true aswer is that its complicated. Upscaling algorithms are quite good now. The following are some things that might affect what resolution is appropriate.

- Printer
- Paper
- Viewing distance
- Type of photo
- Detail level of photo (not strictly resolution but how important the details are to the image.)

[JensE]

There is no universal answer, it highly depends on the printing material, subject and presentation. You can print a huge banner from a K-1 shot if it's hung in a way that there are a few meters viewing distance. The rougher your surface, the less resolution is visible, so canvas is a lot more forgiving than glossy printing paper, see the discussion in K5 with 5Mb File JPG how large can I print on Canvas - PentaxForums.com or 48 inch Enlargement - PentaxForums.com.

For paper prints, or in fact any medium, that can be viewed up close, I wouldn't worry at all with 300 DPI image resolution, i.e. 24.5"x16.4" for the K-1. On matte paper or presentation with (typically) some distance, things look totally fine at about twice that (linearly, 4x area), but that is from where I may consider small test prints of critical parts of the image - highly dependent on subject.

[Rondec]

I think house has the basic answer. Printing at 300 dpi you would get a 24 by 16 inch image with 36 megapixels. Of course you can print larger than that if you want -- most people view large prints from a bit of a distance and so they won't notice. Of course there is software that can help up-resing your image too.

[Sandy Hancock]

I have made quite a few prints at home at 300dpi on A3 paper from KP files. I can't see any problems with even close inspection, and I can't really tell them from the K-1 images.

I'll let you know if that changes when I get my A2+ printer

[acoufap]

Since different aspects have to be considered in the equation, it‘s not really possible to answer in one or two sentences.

Some years ago I had a closer look at this topic and wrote a blog post on my website about it - in german language. If you’re interested in reading it, maybe google translate helps and you may find an appropriate answer to your question?!

[noelpolar]

I seem to do ok with 150 dpi on canvas.

[biz-engineer]

There is the relative enlargement , viewing distance , image detail content etc. as mentioned above.

In absolute terms, experience shows that pixel count comes last as enlargement limit.

1) What comes first is lens CA => manual CA correction (automatic correction only does a partial job).
2) Lens corner sharpness (lack of) shows second, local sharpening can help a bit, but what can be done is limited
3) Eventual diffraction softening can show up depending on aperture

4) Pixel pitch vs image detail (contour description, up-sampling avoid visible pixelation, sharpening has limits

Print at 150 ppi still delivers good quality if lens is sharp corner to corner or in case of center square crop (removing softer / fuzzy area of image).
Print at 300 ppi is overkill for 100% sharp lens, 200 ppi is very good already. Having said that , sharpness drops from center to corners for all lenses, to lesser extent for the best lenses (e.g macro lenses).
Lens circular properties vs rectangle sensor plays such role that a square crop can be printed at the same size as the long size of a 3:2 print of an image capture with the same lens and same camera.

Examples of prints all upsampled at 300 ppi , with optimal sharpening / unsharpmasking:
- K1 D-FA 28-105 print 28x41", ISO200, @ 28mm f10: softness in corners visible, some minimal diffraction (softening tiny details)

- K1 D-FA 28-105 print 24x36", @ 28mm f8: very good perceived quality edge to edge (corner softness almost invisible with best efforts)
- K1 D-FA 28-105 print 32x32", @ 35mm f8 center square crop: very good quality edge to edge , that's ~150 ppi (4912/32).

- K1 HD-FA 35 2 print 28x41", @ f8: very good quality edge to edge.
- K1 D-FA 100 macro @ f8, print 24x36": to quality edge to edge


- K3 Tamron 17-50 SP @ 17mm f8, print 19x28": square center of print is crisp, visible softness in corners and top/bottom of frame long side.
- K3 DA 15 ltd f11, print 19x28": square center of print is good, distracting fuzzy corners very visible.
- K3 Tamron 17-50 SP @ 50mm f5.6, ISO 100, shutter speed 1/500th, print 20x30", very sharp across the frame
- K5 DA 17-70 @ 17mm f8, ISO100 (long exposure), print 20x30", sharp in center, distracting fuzz + CA in corners.
- K200D, DA 18-250 @ 35mm, ISO 800, print 20x30", sharp in center, bits of softness visible in corners, but CCD noise limits overall image crispness.
- K200D, DA 18-250 @ 135mm, f8, ISO200, print 20x30", sharpness in center, visible fuzz at corners and the 4 edges of the frame (lens is soft at 135 , except decently sharp in center)

With mediocre lens, the 3:2 aspect ratio enlargement can be enlarged the same as center square crop, simply due to edges and corners limiting the enlargement.
With edge to edge sharp lens, same camera, image print can be enlarged 1.5x as much as same shot taken with low end not corner to corner sharp lens.
So , the lens is big deal to such an extent that you could print larger from a 24Mp camera and sharp primes, than from a 50Mp camera with an entry level zoom not used at it's maximum optical performance.
Up-sampling prevent pixelation, but doesn't help solve lens resolution drop from center to corners.

[StiffLegged]

I read different opinions on this, but 24MP should print to 24” on the long side as long as you’re not cropping much or preferably not cropping at all. Perhaps it would be more accurate to say 16” on the short side to allow for 5:4 or square crop, 24” on the long side for 3:2 or 16:9. I also do think some people talk about this as if viewing the result with Sherlock Holmes’s magnifying glass.

[The Squirrel Mafia]

I have 30x45 prints out of my 16MP Pentax K-50 that look quite nice. They were non-cropped low ISO images.

[DrawsACircle]

I shot these pictures with my K-70. I know it’s not quite the same as pictures you would put in a frame, but the result is actually pretty good, lots of sharp details in the pictures.

[The Squirrel Mafia]

^ Nice!


And there you have it. The proof is in the pudding.

[texandrews]

Let me amplify several things from his and other posts:

• the scene itself dictates a great deal. You can "get away with" lower ppi output, maybe much lower, if it's a low contrast, foggy scene that's very atmospheric. The reverse if it's a scene of high detail. Also, content (different from subject matter) may also allow for leeway or not.
• viewing distance is very relevant
• context is very important. For art prints meant to be seen by viewers in galleries, they may be scrutinizing the prints pretty closely. For casual things that are over the couch viewers may be much more forgiving, or even unable to view closely. Don't expect people will not look closely if a scene is inviting close inspection and there are no barriers to such, however.
• intended impact is a subset of context. The marvelous RC aircraft images above have such impact, combined with a specific context and audience, plus existing in the action genre, that all of that would mitigate or even evaporation printing detail niceties.